黄土高原部分地区180－73万年间孢粉植物群和环境演变初探

根据黄土高原３个剖面的孢粉资料及测年数据，恢复了本区１８０－７３万年期间的植被面貌。在此基础上，结合中国和全球其它地区的孢粉、构造、地层、水系演化和火山活动等特征。将此期间植被、气候和环境的演化划分为３个主旋回，６个主要演化阶段，１０个亚阶段和５个事件。初步认识到，该时间段的气候环境演化有较大波动，且这些变化不限于局部地区，而是区域性的，是多种因素（内外动力）作用的结果，且有规律可循。

A PRELIMINARY STUDY ON POLYNOFLORA AND ENVIRONMENTAL EVOLUTION OF LOESS PLATEAU BETWEEN 1.8 Ma TO 0.73 Ma

The palaeovegetation during 1.80-0.73Ma has been reconstructed according to sporopollen data and dating results from the typical loess sections on the loess plateau (including the Yandonggou section in Lanzhou,the Xi'an and Linxia sections) .The evolution of vegetation,climate and environment during 1.80-0.73Ma can he divided into 3 main cycles,which are 1.80-1.40,1.40 - 1.12 and 1.12-0.73 Ma in age,based on results from other studies on sporopollen , tectonics,sedimentary stratigraphy, drainage system evolution and volcanic activities in China and the Northern Hemisphere.It can be further divided into 6 main evolution stages, which are 1.80-1.67,1.67-1.40,1.40-1.20,1.20-1.12,1.12-0.85 and 0.85-0.73 Ma.In addition,10 substages and 5 events also can be distinguished.The processes of climatic and environmental changes show strong oscillations.A comparison between the data obtained from different places suggests that the environmental changes are of regional to global significance.